Cinematographic apparatus



May 22, 1951 J. M. ANDREAS CINEMATOGRAPHIC APPARATUS .2 Sheets-Sheet 1Filed Nov. 20, 1948 rig/szm y 22, 1951 J. M. ANDREAS 2,553,841

CINEMATOGRAPHIC APPARATUS Filed Nov. 20, 1948 2 Sheets-Sheet 2 jg (5 1/3j Patented May 22, 1951 CINEMATOGRAPHIC APPARATUS John M. Andreas,Pasadena, Calif., assignor to Technicolor Motion Picture Corporation,Hollywood, Calif., a corporation of California Application November 20,1948, Serial No. 61,253

Claims.

This invention relates to the art of printing sound tracks on motionpicture films. With the constant-density-variable area type of soundreproduction it is by definition necessary to keep the sound-trackdensity equal to a constant ref erence density so that the light valuesreceived by the photo-cell of the sound head in the motion pictureprojector will not be modulated by variations in the density of thetrack. Likewise it is essential that the modulations in avariabledensity sound track be related to a fixed reference density suchthat a given variation from that density will represent a certainvariation in amplitude. It has formerly been thought necessary todevelop the printed sound record before testing its density for thepurpose of controlling the printing exposure in order to eliminate theabove-mentioned undesirable variations. However, owing to the delayduring the developing and finishing processes a great many feet of filmmay be printed incorrectly before the density test reveals the incorrectexposure. The larger the volume of film that is being printed and thegreater the speed at which it is printed the more imperative it becomesfor the density test to discover quickly and accurately the improperexposure.

Objects of the present invention are to provide a quick and accuratemeans of discovering undesirable variations in the density of a printedsound track, and to provide a density test which will permit a promptcorrection of errors.

The present invention concerns a system of producing sound tracksemploying a motion picture film strip which is coated in the sound-trackarea with a print-outemulsion and involves apparatus for producing asound record having a portion of constant reference density comprising adevice for printing the sound track by photographic exposure of the areaso as to produce a print-out record, this device including an adjustablesource of exposing light, means for controlling the eifective intensityof this light, and a densitometer for testing the light absorptivequalities of the reference density portion of the exposed butundeveloped record including as a measuring illuminant a source ofradiation to which the print-out emulsion is not sensitive, wherebyvariations in the reference density of the print-out record may bedetermined prior to further photographic treatment and the exposinglight controlled to produce the desired reference density in thereference portion of the record. This said portion of constant referencedensity may be a strip parallel to or a marginal portion of the soundtrack such as the constant-width constant-density margin of a variablearea sound track or a like margin or strip beside a variable densitysound track.

In a further aspect the apparatus includes sound-track developing means,the densitometer being arranged ahead of the developing means so thatvariations in the density of the reference portion may be determinedprior to development.

In another aspect the invention involves the method of producing a soundtrack which comprises printing a print-out sound record in the emulsion,testing the light-absorptive qualities of that record by means ofradiation to which the emulsion is not sensitive and controlling theprinting exposure in accordance with the test.

For the purpose of illustration typical embodiments of the invention areshown in the accompanying drawings in which Fig. l is a schematicdiagram of apparatus for printing picture and sound records;

Fig. 2 is a schematic diagram of the densitometer;

Fig. 3 is a view of a double width 16 mm. film strip carrying twovariable Width sound tracks;

Fig. 4 is an enlarged view of a portion of the sound tracks; and

Fig. 5 is a schematic diagram of another embodiment of the invention.

The particular embodiment of the invention shown in Figs. 1 and 2involves an imbibition machine having an endless pin belt I traveling inan orbital path over drums 2 and 3, the belt having teeth 5 adapted tofit in the sprocket holes of films. The blank film B to be printed isfed from a supply roll i into a water tank 9 where the film loops backand forth over a series of rollers l I to permit the gelatin coating tosoak up a predetermined amount of moisture. A matrix M, carrying pictureas well as sound records in the form of gelatin relief, is fed from thesupply roll I2 through a dye tank i3 where it takes on dye in conformitywith the relief, thence through a water tank M to rinse oif superficialdye and thence through the water tank 9. The film B to be printed is fedto the belt between two pressure rollers 4 which seat the film on thebelt, and the matrix M is fed to the belt between the pressure rolls 5which seat the matrix on the film B.

After traveling together long enough for the dye in the picture andsound track areas to transfer from the matrix M to the blank B the twofilm are fed from the belt over a roller l8 into a drying box I9 wherethey are separated, the matrix M looping back and forth over rolls 2%while drying and then feeding to a take-up roll 22, and the blank Blooping back and forth over a series of rolls 23 and then feeding past adevice It for applying a sensitizing solution to the sound track Zone ofthe film. Preferably the sensitizer is a solution of light-sensitiveferric iron salts in combination with a ferricyanide, although otheremulsions of the print-out type such as bichromate salts, silvercitrate, tartrate, oxalate or chloride, and kallitype emulsions may beused. The sensitized blank film B is then dried in tank 8 and passedthrough the exposure box 16 containing a light source I! for exposingthe sound track zone of the film B through the dye sound track imbibedon the blank between rollers 6 and 18 as above described. The exposureis made from the face of the film B instead of the back because the dyeimage is confined largely to the surface of the coating on the filmwhereas the sensitizer has penetrated deeper in the film. The strip B isthen fed through a densitometer 24, and thence through the developingand finishing tanks 25 and 26. When the pictures on the film B areprinted with a single color, the blank may then be dried and fed to atake-up roll. However, in color printing one or more additional colorsmay be printed on blank B after it leaves the tank 25. In a two-colorprocess involving red-orange and blue-green color aspect records thefirst color with which the sound track is printed, is preferablyblue-green. In this case the tank 29 will be a water bath wherein asecond matrix M carrying the redorange dye is rinsed and the two films Band M seated upon the pin belt for imbibition of the red-orange picturerecord on the blank B. After the second dye is transferred the secondmatrix M and the printed blank B are separated in the dry box 3| andtaken up on rolls 33 and 32 respectively.

According to the present invention the visible record which is producedin the print-out emulsion by exposure alone is subjected to a densitytest immediately after exposure. Whereas in ordinary black and Whitesilver processes the latent record is invisible and cannot be measureduntil after its development, the print-out record of a blue printemulsion or the like is clearly visible and may be measured immediatelyafter printing. Although the density of the print-out record is notequal to that of the final developed record, it will give an accurateprediction of what the density of the final record will be.

Fig. 2 shows in detail the optical system used in the densitometer whichincludes a source of radiant energy a pair of condensing lenses 52between which is interposed a filter 53 to exclude radiation to whichthe undeveloped emulsion may be sensitive, a mask 54 having an aperture55, an achromatic objective 56, and a photocell 5'! sensitive to theradiation passed by the filter. Light from the lamp is gathered by thecondenser, filtered, fills the aperture, passes through an achromaticobjective which images the aperture on the film, passes through thefilm, and then reaches the photocell. The light energy values receivedby the photocell are amplified in an electronic circuit indicated inFig. 1 by the box labelled AMP and used to vary the reading on anammeter indicated by the box labelled Meter. The ainmeter may give adensity reading, or may be set at a mid-scale null which corresponds tothe desired reference density of the sound track, and used to indicateany variations from the desired density.

One type of sound record suitable for use with the present invention isillustrated in Figs. 3 and i. This record comprises a double-width 16mm. film strip carrying two sound records along the center of the strip.As shown in Fig. 4, the finished double sound record includes twomarginal stripes 4| of constant width, two sound records d2 of variableWidth and a center stripe 43' of constant width. Subsequent to printingthe sound and picture records the strip is divided longitudinallythrough the center stripe into two conventional 16 mm. strips.Preferably it is the density of this center stripe which is measuredprior to the division, however the constant Width margin of the soundrecord on a double 16 mm. or a conventional 35 mm. film, or the variablewidth sound record itself may be measured in some cases.

In addition, a marginal stripe present with or incorporated in avariable density sound track may be tested. This stripe may be of anyfixed density which transmits light values within the range of the soundhead photocell. A variation in this reference density indicates that allthe density values will be incorrect. Normally, the reference portion isa marginal area printed in the upper region of the density range.However, by suitable arrangement of the printing device a stripe orportion may be printed of a :y desired density value, for instance themid-range density.

A rheostat or similar current regulating device is provided for thepurpose of controlling the intensity of the printing lamp ll. Where ablueprint typc emulsion is used it is customary to employ several strongmercury vapor lamps. In this case it may be the last of the lamps which.is controlled. The operator of the printing machine observes the readingon the densitometer and adjusts the rheostat accordingly. Preferably thedensitometer is located immediately after the last printing lamp inorder to reduce the delay between exposure and testing to a minimum.

If desired the amplified photocell response may be applied to anautomatic controlling device which adjusts the effective intensity ofthe printing lamp in accordance with the response of the photocell.

A preferred embodiment of the invention is illustrated in Fig. 5 whichinvolves a cinematographic contact printing machine having an endlessbelt lfii traveling in an orbital path over drums I62 and Hit, the belthaving teeth pins adapted to fit in the sprocket holes of the films. Thefilm strip P to the printed may be sensitized in the sound track areawith a blue print type emulsion which may comprise potassiumferricyanide and ferric ammonium oxalate. The printing negative Ncarries a variable area soundtrack record, preferably a high qualityblack and white silver negative on fine grain ray-base film. Both stripsP and N are dry when their supply reels H2 and ii respectively aremounted in the printing machine. The film P to be printed is fed fromthe supply reel H2 over guide rolls I06 and it??? to the seating rollerI04. A pivoted arm E59 actuated by the compression spring H0 holds theseating roller its yieldingly against the drum N32. The film strip N isfed over the guide roll Iii, the sprocket H3 and the floating pulley H4and then is seated simultaneously with the strip P on the pin belt IOIby the seating roller I54. Owing to the fact that the negative N shrinkssomewhat in development, the floating pulley H4 is supported on apivoted arm l l6 which is urged by the spring I33 to stretch the strip Nbetween the sprocket l 13 and the seating roller I04.

Both film strips are then carried on the belt I!!! under a series ofexposing ill, one or more of which may be varied in intensity by meansof a rheostat H5 which controls power supplied at the tern'iinals and c.Aft-e: A issing under the lamps the two strips leave the pin. be at thefloating roller H8 which is supported like the seating roller 35. Thenegative strip N then feeds over the tension pulley H9, the sprocket I25and the guide rolls l2! and I23 to the takeup reel I22. After leavingthe roller i it the positive strip P is fed over the guide rolls iZd andE25 through the densitorneter i241, thence over the guide roll ii? tothe take-up reel M2.

The densitometer ii-lcomprises a source of light lti, a reflector 5t,condenser lenses H52, a red filter kid, a mask having a slit i5 5,objective lens 15% and a photo-sensitive device IE'J. The filter passeslight to which the still undeveloped but visible print--out record onthe film strip P is not sensitive. Such light passing through the slitIE5 is imaged on the print-out sound track record of the film strip Pthrough a refer nce portion of constant width as hereinbefore describedand falls on the photosensitive tube I51. The response of the photo tubei5? is amplified in an electronic circuit are and applied to a meterI29. Undesirable variations in the density of the print-out record areindicated on the meter. The operator of the printing machine thenadjusts the rheost-at I it according to his observation of the meteruntil a correct density indication is given by the meter 129.

It should be understood that the present dis closure is for the purposeof illustration only, and that this invention includes all modificationsand equivalents which fall within the scope or the appended claims.

I claim:

1. Apparatus for producing a sound record having a portion of constantreference density in a motion picture film strip sensitized in its soundrecord area with a print-out emulsion which comprises a device forprinting a sound track by photographic exposure of said area of theemulsion so as to produce a print-out sound record, an adjustable sourceof exposure light, means for controlling the effective intensity of saidsource, sound track developing means, and a densitometer arranged aheadof said developing means for testing the light absorptive qualities ofsaid portion of the exposed but undeveloped record, said densitometerincluding as a measuring illuminant a source of radiation to which theemulsion is not sensitive and optical means for directing a beam of saidradiation only on said portion, whereby variations in density of theprint-out sound record may be determined prior to further photographictreatment, and said exposure light source of the printer con" trolledaccording tothe density of the record produced by said exposure toproduce the desired reference density in said record.

2. Apparatus for producing a sound record having a portion of constantreference density in a motion picture film strip coated in its soundrecord area with a print-out emulsion, which comprises means for feedingthe strip along a path, a device adjacent the path for printing a soundtrack by photographic exposure of said area of the emulsion so as toproduce a print-out sound record, an adjustable source of exposurelight, means for controlling the effective intensity of said source,sound track developing means on the path, and a densitometer closelyadjacent said printer and ahead of the developing means on said path fortesting the light absorptive qualities of said portion of the exposedbut undeveloped record, said densitometer ineluding as measuringilluminant a source of radiation to which the emulsion is not sensitiveand optical means for directing a beam of said radiation only on saidportion, whereby variations in density of the print-out sound record maybe determined immediately after exposure and prior to development, andthe printer controlled according to the density of the record producedby said exposure to produce the desired reference density in saidrecord.

3. In the art of producing a sound record having a portion of constantreference density in a motion picture film strip sensitized in its soundtrack area with a print-out emulsion the method which comprises printinga sound track by photographic exposure of said emulsion so as to producea printout record, immediately testing the light absorptive qualities ofsaid portion of re exposed but undeveloped record by means of radiationto which the emulsion is not sensitive and controlling the printingexposure according to said light absorptive qualities, wherebyvariations in density of the print-out sound record may be determinedprior to further photographic treatment, and the printing exposurevaried according to th density of the record produced by said exposureto produce the desired reference density in said record.

1. In the art of producing a constant densityvariable area sound recordin a motion picture film strip coated in the sound track area with aprint-out emulsion the method which comprises printing a sound track byphotographic exposure of said emulsion so as to produce a print-outrecord, immediately testing the light absorptive qualities of theexposed but undeveloped record by means of radiation to which theemulsion is not sensitive, and controlling the printing exposureaccording to said light absorptive qualities, whereby variations indensity of the printout sound record may be determined prior to furtherphotographic treatment, and the printing exposure varied according tothe density of the record produced by said exposure to produce thedesired density in said record.

5. In the art of producing a sound record having a portion of constantreference density in a motion picture film strip sensitized in its soundtrack area with a print-out emulsion, the method which comprisesprinting a sound track by photographic exposure of said emulsion so asto produce a print-out record including the aforesaid reference portion,directing only on said portion a beam of radiation to which the emulsionis not sensitive, measuring the light-absorptive qualities of saidportion of the exposed but undeveloped record by means of said beam andcontrolling the printing exposure according to the light-absorptivequalities of the record produced by said exposure, whereby variations indensity of the print-out record may be determined prior to furtherphotographic treatment, and the printing exposure varied to produce thedesired reference density in said record.

JOHN M. ANDREAS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,908,610 Jones et al. May 9,1933 1,966,322 Tuttle July 10, 1934 2,083,675 Ville June 15, 19372,101,932 Eggert et a1 Dec. 14, 1937 2,413,218 Coroniti Dec. 24, 1946FOREIGN PATENTS Number Country Date 406,664 Great Britain Feb. 28, 1934498,427 Great Britain Jan. 9, 1939

